A team led by researchers with the National Oceanic and Atmospheric Administration (NOAA) have determined that marine heat waves can occur deep underwater, as reported in a paper published in Nature Communications.
“Researchers have been investigating marine heat waves at the sea surface for over a decade now," Dillon Amaya, NOAA research scientist, said in a NOAA press release issued March 13. "This is the first time we’ve been able to really dive deeper and assess how these extreme events unfold along shallow seafloors."
“The Blob,” a marine heat wave that occurred from 2013 to 2016 in the northeastern Pacific, prompted research on the extreme warming of ocean surface waters, the release reported. The new research from NOAA, assessing bottom marine heat waves in the continental shelf waters surrounding North America, found that just like ocean surface waters, marine heat waves happen deep underwater.
The marine heat waves significantly impact the health of ocean ecosystems, disrupting the productivity and distribution of organisms, from plankton to whales, according to the NOAA release. Most research has focused on temperature extremes at the ocean’s surface, which are easier to measure with satellites, ships, and buoys. However, about 90% of the excess heat from global warming has been absorbed by the ocean, causing marine heat waves to become 50% more frequent over the past decade, NOAA reports.
This study’s findings highlight the need to better understand and predict bottom marine heat waves’ intensity, duration, and physical drivers, according to scientists interviewed for the Nature Communications article. This information can help protect vulnerable marine ecosystems and commercial fisheries that rely on them.
On the continental shelves around the North America continent, the research team from NOAA, the Cooperative Institute for Research in Environmental Sciences (CIRES) and the National Center for Atmospheric Research (NCAR) found that bottom marine heat waves are likely to persist longer than those on the surface. Marine heat waves can occur on the bottom and the surface at the same time in the same location, especially in shallower locations where the waters mingle, according to the release.
Bottom marine heat waves can occur with little warming at the surface, which has serious implications for commercially important fisheries and their management, the release reported.
